package main

import (
	"fmt"
	"net/http"
	"strings"

	"github.com/go-git/go-git/v5/plumbing"
	"github.com/go-git/go-git/v5/plumbing/filemode"
	"github.com/go-git/go-git/v5/plumbing/format/diff"
	"go.lindenii.runxiyu.org/lindenii-common/misc"
)

type usable_file_patch struct {
	From   diff.File
	To     diff.File

	Chunks []diff.Chunk

	Chunks []usable_chunk
}

type usable_chunk struct {
	Operation diff.Operation
	Content   string

}

func handle_repo_commit(w http.ResponseWriter, r *http.Request, params map[string]any) {
	group_name, repo_name, commit_id_specified_string := params["group_name"].(string), params["repo_name"].(string), params["commit_id"].(string)
	repo, description, err := open_git_repo(r.Context(), group_name, repo_name)
	if err != nil {
		http.Error(w, "Error opening repo: "+err.Error(), http.StatusInternalServerError)
		return
	}
	params["repo_description"] = description
	commit_id_specified_string_without_suffix := strings.TrimSuffix(commit_id_specified_string, ".patch")
	commit_id := plumbing.NewHash(commit_id_specified_string_without_suffix)
	commit_object, err := repo.CommitObject(commit_id)
	if err != nil {
		http.Error(w, "Error getting commit object: "+err.Error(), http.StatusInternalServerError)
		return
	}
	if commit_id_specified_string_without_suffix != commit_id_specified_string {
		patch, err := format_patch_from_commit(commit_object)
		if err != nil {
			http.Error(w, "Error formatting patch: "+err.Error(), http.StatusInternalServerError)
			return
		}
		fmt.Fprintln(w, patch)
		return
	}
	commit_id_string := commit_object.Hash.String()

	if commit_id_string != commit_id_specified_string {
		http.Redirect(w, r, commit_id_string, http.StatusSeeOther)
		return
	}

	params["commit_object"] = commit_object
	params["commit_id"] = commit_id_string

	parent_commit_hash, patch, err := get_patch_from_commit(commit_object)
	if err != nil {
		http.Error(w, "Error getting patch from commit: "+err.Error(), http.StatusInternalServerError)
		return
	}
	params["parent_commit_hash"] = parent_commit_hash.String()
	params["patch"] = patch

	// TODO: Remove unnecessary context
	// TODO: Prepend "+"/"-"/" " instead of solely distinguishing based on color
	usable_file_patches := make([]usable_file_patch, 0)
	for _, file_patch := range patch.FilePatches() {
		from, to := file_patch.Files()
		if from == nil {
			from = fake_diff_file_null
		}
		if to == nil {
			to = fake_diff_file_null
		}

		chunks := []usable_chunk{}
		for _, chunk := range file_patch.Chunks() {	
			content := chunk.Content()
			if len(content) > 0 && content[0] == '\n' {
				content = "\n" + content
			} // Horrible hack to fix how browsers newlines that immediately proceed <pre>
			chunks = append(chunks, usable_chunk{
				Operation: chunk.Type(),
				Content:   content,
			})
		}

		usable_file_patch := usable_file_patch{

			Chunks: file_patch.Chunks(),

			Chunks: chunks,

			From:   from,
			To:     to,
		}
		usable_file_patches = append(usable_file_patches, usable_file_patch)
	}
	params["file_patches"] = usable_file_patches

	render_template(w, "repo_commit", params)
}

type fake_diff_file struct {
	hash plumbing.Hash
	mode filemode.FileMode
	path string
}

func (f fake_diff_file) Hash() plumbing.Hash {
	return f.hash
}

func (f fake_diff_file) Mode() filemode.FileMode {
	return f.mode
}

func (f fake_diff_file) Path() string {
	return f.path
}

var fake_diff_file_null = fake_diff_file{
	hash: plumbing.NewHash("0000000000000000000000000000000000000000"),
	mode: misc.First_or_panic(filemode.New("100644")),
	path: "",
}

/* Base styles and variables */
html {
	font-family: sans-serif;
	background-color: var(--background-color);
	color: var(--text-color);
	--background-color: hsl(0, 0%, 100%);
	--text-color: hsl(0, 0%, 0%);
	--link-color: hsl(320, 50%, 36%);
	--light-text-color: hsl(0, 0%, 45%);
	--darker-border-color: hsl(0, 0%, 72%);
	--lighter-border-color: hsl(0, 0%, 85%);
	--text-decoration-color: hsl(0, 0%, 72%);
	--darker-box-background-color: hsl(0, 0%, 92%);
	--lighter-box-background-color: hsl(0, 0%, 95%);
	--primary-color: hsl(320, 50%, 36%);
	--primary-color-contrast: hsl(320, 0%, 100%);
	--danger-color: hsl(0, 50%, 36%);
	--danger-color-contrast: hsl(0, 0%, 100%);
}

/* Dark mode overrides */
@media (prefers-color-scheme: dark) {
	html {
		--background-color: hsl(0, 0%, 0%);
		--text-color: hsl(0, 0%, 100%);
		--link-color: hsl(320, 50%, 76%);
		--light-text-color: hsl(0, 0%, 78%);
		--darker-border-color: hsl(0, 0%, 35%);
		--lighter-border-color: hsl(0, 0%, 25%);
		--text-decoration-color: hsl(0, 0%, 30%);
		--darker-box-background-color: hsl(0, 0%, 20%);
		--lighter-box-background-color: hsl(0, 0%, 15%);
	}
}

/* Global layout */
body {
	margin: 0;
}
html, code, pre {
	font-size: 1rem; /* TODO: Not always correct */
}

/* Footer styles */
footer {
	margin-top: 1rem;
	margin-left: auto;
	margin-right: auto;
	display: block;
	padding: 0 5px;
	width: fit-content;
	text-align: center;
	color: var(--light-text-color);
}
footer a:link, footer a:visited {
	color: inherit;
}

/* Padding containers */
.padding-wrapper {
	margin: 1rem auto;
	max-width: 60rem;
	padding: 0 5px;
}
.padding {
	padding: 0 5px;
}

/* Link styles */
a:link, a:visited {
	text-decoration-color: var(--text-decoration-color);
	color: var(--link-color);
}

/* Readme inline code styling */
#readme code:not(pre > code) {
	background-color: var(--lighter-box-background-color);
	border-radius: 2px;
	padding: 2px;
}

/* Table styles */
table {
	border: var(--lighter-border-color) solid 1px;
	border-spacing: 0px;
	border-collapse: collapse;
}
table.wide {
	width: 100%;
}
td, th {
	padding: 3px 5px;
	border: var(--lighter-border-color) solid 1px;
}
th, thead, tfoot {
	background-color: var(--lighter-box-background-color);
}
th[scope=row] {
	text-align: left;
}
tr.title-row > th, th.title-row, .title-row {
	background-color: var(--darker-box-background-color);
}
td > pre {
	margin: 0;
}
td#readme > *:last-child {
	margin-bottom: 0;
}
td#readme > *:first-child {
	margin-top: 0;
}

/* Table misc and scrolling */
.commit-id {
	font-family: monospace;
}
.scroll {
	overflow-x: auto;
}

/* Toggle table controls */
.toggle-table-off, .toggle-table-on {
	display: none;
}
.toggle-table-off + table > thead > tr > th, .toggle-table-on + table > thead > tr > th {
	padding: 0;
}
.toggle-table-off + table > thead > tr > th > label, .toggle-table-on + table > thead > tr > th > label {
	width: 100%;
	display: inline-block;
	padding: 3px 0;
	cursor: pointer;
}
.toggle-table-off:checked + table > tbody {
	display: none;
}
.toggle-table-on + table > tbody {
	display: none;
}
.toggle-table-on:checked + table > tbody {
	display: table-row-group;
}

/* Diff/chunk styles */
.chunk-unchanged {
	color: grey;
}
.chunk-addition {

	color: green;

	background-color: green;

}
@media (prefers-color-scheme: dark) {
	.chunk-addition {

		color: lime;

		background-color: lime;

	}
}
.chunk-deletion {

	color: red;

	background-color: red;

}
.chunk-unknown {

	color: yellow;

	background-color: yellow;

}
pre.chunk {
	margin-top: 0;
	margin-bottom: 0;
}

/* Toggle content sections */
.toggle-on-wrapper {
	border: var(--lighter-border-color) solid 1px;
}
.toggle-on-toggle {
	display: none;
}
.toggle-on-header {
	cursor: pointer;
	display: block;
	width: 100%;
	background-color: var(--lighter-box-background-color);
}
.toggle-on-header > span {
	padding: 3px 5px;
	display: inline-block;
}
.toggle-on-content {
	display: none;
}
.toggle-on-toggle:checked + .toggle-on-header + .toggle-on-content {
	display: block;
}

/* File display styles */
.file-patch + .file-patch {
	margin-top: 0.5rem;
}
.file-content {
	padding: 3px 5px;
}
.file-header {
	font-family: monospace;
}

/* Form elements */
textarea {
	box-sizing: border-box;
	background-color: var(--lighter-box-background-color);
	resize: vertical;
}
textarea,
input[type=text],
input[type=password] {
	font-family: sans-serif;
	font-size: smaller;
	background-color: var(--lighter-box-background-color);
	color: var(--text-color);
	border: none;
	padding: 0.3rem;
	width: 100%;
	box-sizing: border-box;
}
td.tdinput, th.tdinput {
	padding: 0;
}
td.tdinput textarea,
td.tdinput input[type=text],
td.tdinput input[type=password],
th.tdinput textarea,
th.tdinput input[type=text],
th.tdinput input[type=password] {
	background-color: transparent;
}

/* Button styles */
.btn-primary {
	background: var(--primary-color);
	color: var(--primary-color-contrast);
	border: var(--lighter-border-color) 1px solid;
	font-weight: bold;
}
.btn-danger {
	background: var(--danger-color);
	color: var(--danger-color-contrast);
	border: var(--lighter-border-color) 1px solid;
	font-weight: bold;
}
.btn-white {
	background: var(--primary-color-contrast);
	color: var(--primary-color);
	border: var(--lighter-border-color) 1px solid;
}
.btn-normal,
input[type=file]::file-selector-button {
	background: var(--lighter-box-background-color);
	border: var(--lighter-border-color) 1px solid !important;
	color: var(--light-text-color);
}
.btn, .btn-white, .btn-danger, .btn-normal, .btn-primary,
input[type=submit],
input[type=file]::file-selector-button {
	display: inline-block;
	width: auto;
	min-width: fit-content;
	border-radius: 0;
	padding: .1rem .75rem;
	font-size: 0.9rem;
	transition: background .1s linear;
	cursor: pointer;
}
a.btn, a.btn-white, a.btn-danger, a.btn-normal, a.btn-primary {
	text-decoration: none;
}

/* Header layout */
header#main-header {
	background-color: var(--lighter-box-background-color);
	display: flex;
	justify-content: space-between;
	align-items: center;
	padding: 10px;
}
header#main-header > div#main-header-forge-title {
	flex-grow: 1;
}
header#main-header > div#main-header-user {
	display: flex;
	align-items: center;
}

{{- define "repo_commit" -}}
<!DOCTYPE html>
<html lang="en">
	<head>
		{{ template "head_common" . }}
		<title>{{ .group_name }}/repos/{{ .repo_name }} &ndash; {{ .global.forge_title }}</title>
	</head>
	<body class="repo-commit">
		{{ template "header" . }}
		<div class="padding-wrapper scroll">
			<table id="commit-info-table">
				<thead>
					<tr class="title-row">
						<th colspan="2">Commit info</th>
					</tr>
				</thead>
				<tbody>
					<tr>
						<th scope="row">ID</th>
						<td>{{ .commit_id }}</td>
					</tr>
					<tr>
						<th scope="row">Author</th>
						<td>{{ .commit_object.Author.Name }} &lt;<a href="mailto:{{ .commit_object.Author.Email }}">{{ .commit_object.Author.Email }}</a>&gt;</td>
					</tr>
					<tr>
						<th scope="row">Author date</th>
						<td>{{ .commit_object.Author.When.Format "Mon, 02 Jan 2006 15:04:05 -0700" }}</td>
					</tr>
					<tr>
						<th scope="row">Committer</th>
						<td>{{ .commit_object.Committer.Name }} &lt;<a href="mailto:{{ .commit_object.Committer.Email }}">{{ .commit_object.Committer.Email }}</a>&gt;</td>
					</tr>
					<tr>
						<th scope="row">Committer date</th>
						<td>{{ .commit_object.Committer.When.Format "Mon, 02 Jan 2006 15:04:05 -0700" }}</td>
					</tr>
					<tr>
						<th scope="row">Message</th>
						<td><pre>{{ .commit_object.Message }}</pre></td>
					</tr>
					<tr>
						<th scope="row">Actions</th>
						<td><pre><a href="{{ .commit_object.Hash }}.patch">Get patch</a></pre></td>
					</tr>
				</tbody>
			</table>
		</div>
		<div class="padding-wrapper">
			{{ $parent_commit_hash := .parent_commit_hash }}
			{{ $commit_object := .commit_object }}
			{{ range .file_patches }}
				<div class="file-patch toggle-on-wrapper">
					<input type="checkbox" id="toggle-{{ .From.Hash }}{{ .To.Hash }}" class="file-toggle toggle-on-toggle">
					<label for="toggle-{{ .From.Hash }}{{ .To.Hash }}" class="file-header toggle-on-header">
						<span>
							{{ if eq .From.Path "" }}
								--- /dev/null
							{{ else }}
								--- a/<a href="../tree/{{ .From.Path }}?commit={{ $parent_commit_hash }}">{{ .From.Path }}</a> {{ .From.Mode }}
							{{ end }}
							<br />
							{{ if eq .To.Path "" }}
								+++ /dev/null
							{{ else }}
								+++ b/<a href="../tree/{{ .To.Path }}?commit={{ $commit_object.Hash }}">{{ .To.Path }}</a> {{ .To.Mode }}
							{{ end }}
						</span>
					</label>
					<div class="file-content toggle-on-content scroll">
						{{ range .Chunks }}

							{{ if eq .Type 0 }}

							{{ if eq .Operation 0 }}

								<pre class="chunk chunk-unchanged">{{ .Content }}</pre>

							{{ else if eq .Type 1 }}

							{{ else if eq .Operation 1 }}

								<pre class="chunk chunk-addition">{{ .Content }}</pre>

							{{ else if eq .Type 2 }}

							{{ else if eq .Operation 2 }}

								<pre class="chunk chunk-deletion">{{ .Content }}</pre>
							{{ else }}
								<pre class="chunk chunk-unknown">{{ .Content }}</pre>
							{{ end }}
						{{ end }}
					</div>
				</div>
			{{ end }}
		</div>
		<footer>
			{{ template "footer" . }}
		</footer>
	</body>
</html>
{{- end -}}