package gitea_test

import (
	"context"
	"encoding/json"
	"io"
	"net/http"
	"net/http/httptest"
	"testing"

	"gitea.d-ma.be/mathias/gitea-mcp/internal/gitea"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

const pullFixture = `{
	"number": 7,
	"title": "Add feature X",
	"body": "This PR adds feature X",
	"html_url": "http://example.com/pulls/7",
	"state": "open",
	"draft": false,
	"head": {"ref": "feat/x"},
	"base": {"ref": "main"}
}`

func TestCreatePullRequestSendsPayload(t *testing.T) {
	var captured []byte
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		assert.Equal(t, "/api/v1/repos/o/r/pulls", r.URL.Path)
		assert.Equal(t, http.MethodPost, r.Method)
		var err error
		captured, err = io.ReadAll(r.Body)
		require.NoError(t, err)
		w.WriteHeader(http.StatusCreated)
		_, _ = w.Write([]byte(pullFixture))
	}))
	defer srv.Close()

	c := gitea.NewClient(srv.URL, "tok")
	pr, err := c.CreatePullRequest(context.Background(), "o", "r", gitea.CreatePullRequestArgs{
		Title: "Add feature X",
		Body:  "This PR adds feature X",
		Head:  "feat/x",
		Base:  "main",
		Draft: false,
	})
	require.NoError(t, err)

	var payload map[string]any
	require.NoError(t, json.Unmarshal(captured, &payload))
	assert.Equal(t, "Add feature X", payload["title"])
	assert.Equal(t, "This PR adds feature X", payload["body"])
	assert.Equal(t, "feat/x", payload["head"])
	assert.Equal(t, "main", payload["base"])
	assert.Equal(t, false, payload["draft"])

	assert.Equal(t, 7, pr.Number)
	assert.Equal(t, "Add feature X", pr.Title)
	assert.Equal(t, "http://example.com/pulls/7", pr.HTMLURL)
	assert.Equal(t, "feat/x", pr.Head.Ref)
	assert.Equal(t, "main", pr.Base.Ref)
	assert.Equal(t, "open", pr.State)
	assert.False(t, pr.Draft)
}

func TestGetPullRequest(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		assert.Equal(t, "/api/v1/repos/o/r/pulls/42", r.URL.Path)
		assert.Equal(t, http.MethodGet, r.Method)
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{
			"number": 42,
			"title": "Fix bug Y",
			"body": "Fixes Y",
			"html_url": "http://example.com/pulls/42",
			"state": "open",
			"draft": true,
			"head": {"ref": "fix/y"},
			"base": {"ref": "main"}
		}`))
	}))
	defer srv.Close()

	c := gitea.NewClient(srv.URL, "tok")
	pr, err := c.GetPullRequest(context.Background(), "o", "r", 42)
	require.NoError(t, err)
	assert.Equal(t, 42, pr.Number)
	assert.Equal(t, "Fix bug Y", pr.Title)
	assert.Equal(t, "http://example.com/pulls/42", pr.HTMLURL)
	assert.Equal(t, "fix/y", pr.Head.Ref)
	assert.Equal(t, "main", pr.Base.Ref)
	assert.Equal(t, "open", pr.State)
	assert.True(t, pr.Draft)
}

func TestGetPullRequestFiles(t *testing.T) {
	filesJSON := `[
		{"filename":"main.go","status":"modified","additions":10,"deletions":5},
		{"filename":"README.md","status":"added","additions":20,"deletions":0}
	]`
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		assert.Equal(t, "/api/v1/repos/o/r/pulls/42/files", r.URL.Path)
		assert.Equal(t, http.MethodGet, r.Method)
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(filesJSON))
	}))
	defer srv.Close()

	c := gitea.NewClient(srv.URL, "tok")
	files, err := c.GetPullRequestFiles(context.Background(), "o", "r", 42)
	require.NoError(t, err)
	require.Len(t, files, 2)
	assert.Equal(t, "main.go", files[0].Filename)
	assert.Equal(t, "modified", files[0].Status)
	assert.Equal(t, 10, files[0].Additions)
	assert.Equal(t, 5, files[0].Deletions)
	assert.Equal(t, "README.md", files[1].Filename)
	assert.Equal(t, "added", files[1].Status)
	assert.Equal(t, 20, files[1].Additions)
	assert.Equal(t, 0, files[1].Deletions)
}

func TestGetPullRequestDiff(t *testing.T) {
	rawDiff := "diff --git a/main.go b/main.go\n--- a/main.go\n+++ b/main.go\n@@ -1,2 +1,3 @@\n+package main\n"
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		assert.Equal(t, "/api/v1/repos/o/r/pulls/42.diff", r.URL.Path)
		assert.Equal(t, http.MethodGet, r.Method)
		w.Header().Set("Content-Type", "text/plain")
		_, _ = w.Write([]byte(rawDiff))
	}))
	defer srv.Close()

	c := gitea.NewClient(srv.URL, "tok")
	diff, err := c.GetPullRequestDiff(context.Background(), "o", "r", 42)
	require.NoError(t, err)
	assert.Equal(t, []byte(rawDiff), diff)
}

func TestListPullRequests(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		assert.Equal(t, "/api/v1/repos/o/r/pulls", r.URL.Path)
		assert.Equal(t, "open", r.URL.Query().Get("state"))
		assert.Equal(t, "feat/x", r.URL.Query().Get("head"))
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`[` + pullFixture + `]`))
	}))
	defer srv.Close()

	c := gitea.NewClient(srv.URL, "tok")
	prs, err := c.ListPullRequests(context.Background(), "o", "r", "open", "feat/x", 0, 0)
	require.NoError(t, err)
	require.Len(t, prs, 1)
	assert.Equal(t, 7, prs[0].Number)
	assert.Equal(t, "feat/x", prs[0].Head.Ref)
}

func TestMergePullRequestSuccess(t *testing.T) {
	var captured []byte
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		assert.Equal(t, "/api/v1/repos/o/r/pulls/7/merge", r.URL.Path)
		assert.Equal(t, http.MethodPost, r.Method)
		var err error
		captured, err = io.ReadAll(r.Body)
		require.NoError(t, err)
		w.WriteHeader(http.StatusNoContent)
	}))
	defer srv.Close()

	c := gitea.NewClient(srv.URL, "tok")
	err := c.MergePullRequest(context.Background(), "o", "r", 7, gitea.MergePRArgs{Do: "squash"})
	require.NoError(t, err)

	var payload map[string]any
	require.NoError(t, json.Unmarshal(captured, &payload))
	assert.Equal(t, "squash", payload["Do"])
}

func TestMergePullRequestConflict(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusConflict)
		_, _ = w.Write([]byte(`{"message":"merge conflict"}`))
	}))
	defer srv.Close()

	c := gitea.NewClient(srv.URL, "tok")
	err := c.MergePullRequest(context.Background(), "o", "r", 7, gitea.MergePRArgs{Do: "merge"})
	require.Error(t, err)
	assert.ErrorIs(t, err, gitea.ErrConflict)
}