package tools_test

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

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

const branchCheckExistsResp = `{"name":"feat/x","commit":{"id":"abc","url":"http://example.com"}}`
const createBranchResp = `{"name":"feat/new","commit":{"id":"abc","url":"http://example.com"}}`
const upsertFileResp = `{"content":{"path":"doc.md","sha":"filsha","html_url":"http://example.com/doc.md"},"commit":{"sha":"cmt1","html_url":"http://example.com/commit/cmt1"}}`
const getRepoResp = `{"name":"myrepo","full_name":"owner/myrepo","default_branch":"main"}`

func TestFileWriteBranchCreatesBranchAndFile(t *testing.T) {
	mux := http.NewServeMux()

	// Branch check → 404 (branch doesn't exist)
	mux.HandleFunc("/api/v1/repos/owner/myrepo/branches/feat/new", func(w http.ResponseWriter, r *http.Request) {
		if r.Method == http.MethodGet {
			w.WriteHeader(http.StatusNotFound)
			_, _ = w.Write([]byte(`{"message":"branch not found"}`))
		}
	})

	// Create branch → 201
	mux.HandleFunc("/api/v1/repos/owner/myrepo/branches", func(w http.ResponseWriter, r *http.Request) {
		require.Equal(t, http.MethodPost, r.Method)
		w.WriteHeader(http.StatusCreated)
		_, _ = w.Write([]byte(createBranchResp))
	})

	// New file (no sha) → POST to /contents/{path}
	mux.HandleFunc("/api/v1/repos/owner/myrepo/contents/doc.md", func(w http.ResponseWriter, r *http.Request) {
		require.Equal(t, http.MethodPost, r.Method)
		w.WriteHeader(http.StatusCreated)
		_, _ = w.Write([]byte(upsertFileResp))
	})

	srv := httptest.NewServer(mux)
	defer srv.Close()

	tool := tools.NewFileWriteBranch(gitea.NewClient(srv.URL, "tok"), allowlist.New([]string{"owner"}))
	out, err := tool.Call(context.Background(), json.RawMessage(`{
		"owner":"owner","name":"myrepo","path":"doc.md",
		"content":"hello","branch":"feat/new","base":"main",
		"message":"add doc.md"
	}`))
	require.NoError(t, err)

	var result map[string]any
	require.NoError(t, json.Unmarshal(out, &result))
	assert.Equal(t, "feat/new", result["branch"])
	assert.Equal(t, "doc.md", result["path"])
	assert.Equal(t, "cmt1", result["commit_sha"])
}

func TestFileWriteBranchUsesPutWhenShaProvided(t *testing.T) {
	mux := http.NewServeMux()

	// Branch exists
	mux.HandleFunc("/api/v1/repos/owner/myrepo/branches/feat/existing", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(branchCheckExistsResp))
	})

	// Existing file (sha provided) → PUT
	mux.HandleFunc("/api/v1/repos/owner/myrepo/contents/doc.md", func(w http.ResponseWriter, r *http.Request) {
		require.Equal(t, http.MethodPut, r.Method)
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte(upsertFileResp))
	})

	srv := httptest.NewServer(mux)
	defer srv.Close()

	tool := tools.NewFileWriteBranch(gitea.NewClient(srv.URL, "tok"), allowlist.New([]string{"owner"}))
	out, err := tool.Call(context.Background(), json.RawMessage(`{
		"owner":"owner","name":"myrepo","path":"doc.md",
		"content":"hello","branch":"feat/existing",
		"sha":"oldsha","message":"update doc.md"
	}`))
	require.NoError(t, err)
	require.NotNil(t, out)
}

func TestFileWriteBranchUsesDefaultBaseWhenBaseEmpty(t *testing.T) {
	var createBody []byte
	mux := http.NewServeMux()

	// Branch check → 404
	mux.HandleFunc("/api/v1/repos/owner/myrepo/branches/feat/new", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusNotFound)
		_, _ = w.Write([]byte(`{"message":"not found"}`))
	})

	// GET repo (to resolve default_branch)
	mux.HandleFunc("/api/v1/repos/owner/myrepo", func(w http.ResponseWriter, r *http.Request) {
		require.Equal(t, http.MethodGet, r.Method)
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(getRepoResp))
	})

	// Create branch → capture body to assert old_branch_name
	mux.HandleFunc("/api/v1/repos/owner/myrepo/branches", func(w http.ResponseWriter, r *http.Request) {
		require.Equal(t, http.MethodPost, r.Method)
		var err error
		createBody, err = io.ReadAll(r.Body)
		require.NoError(t, err)
		w.WriteHeader(http.StatusCreated)
		_, _ = w.Write([]byte(createBranchResp))
	})

	// Upsert file
	mux.HandleFunc("/api/v1/repos/owner/myrepo/contents/doc.md", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusCreated)
		_, _ = w.Write([]byte(upsertFileResp))
	})

	srv := httptest.NewServer(mux)
	defer srv.Close()

	tool := tools.NewFileWriteBranch(gitea.NewClient(srv.URL, "tok"), allowlist.New([]string{"owner"}))
	out, err := tool.Call(context.Background(), json.RawMessage(`{
		"owner":"owner","name":"myrepo","path":"doc.md",
		"content":"hello","branch":"feat/new",
		"message":"add doc.md"
	}`))
	require.NoError(t, err)
	require.NotNil(t, out)

	var payload map[string]string
	require.NoError(t, json.Unmarshal(createBody, &payload))
	assert.Equal(t, "main", payload["old_branch_name"])
	assert.Equal(t, "feat/new", payload["new_branch_name"])
}

func TestFileWriteBranchSkipsCreateWhenBranchExists(t *testing.T) {
	var createCallCount atomic.Int32
	mux := http.NewServeMux()

	// Branch check → 200 (branch exists)
	mux.HandleFunc("/api/v1/repos/owner/myrepo/branches/feat/existing", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(branchCheckExistsResp))
	})

	// Create branch — should NOT be called
	mux.HandleFunc("/api/v1/repos/owner/myrepo/branches", func(w http.ResponseWriter, r *http.Request) {
		createCallCount.Add(1)
		w.WriteHeader(http.StatusCreated)
		_, _ = w.Write([]byte(createBranchResp))
	})

	// Upsert file
	mux.HandleFunc("/api/v1/repos/owner/myrepo/contents/doc.md", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusCreated)
		_, _ = w.Write([]byte(upsertFileResp))
	})

	srv := httptest.NewServer(mux)
	defer srv.Close()

	tool := tools.NewFileWriteBranch(gitea.NewClient(srv.URL, "tok"), allowlist.New([]string{"owner"}))
	out, err := tool.Call(context.Background(), json.RawMessage(`{
		"owner":"owner","name":"myrepo","path":"doc.md",
		"content":"hello","branch":"feat/existing",
		"message":"update doc.md"
	}`))
	require.NoError(t, err)
	require.NotNil(t, out)

	assert.Equal(t, int32(0), createCallCount.Load(), "POST /branches should not be called when branch exists")
}

func TestFileWriteBranchAllowlistRejects(t *testing.T) {
	tool := tools.NewFileWriteBranch(gitea.NewClient("http://unused", ""), allowlist.New([]string{"allowed"}))
	_, err := tool.Call(context.Background(), json.RawMessage(`{
		"owner":"evil","name":"repo","path":"f.md",
		"content":"x","branch":"feat/x","message":"msg"
	}`))
	require.Error(t, err)
}

func TestFileWriteBranchRequiresMessage(t *testing.T) {
	tool := tools.NewFileWriteBranch(gitea.NewClient("http://unused", ""), allowlist.New([]string{"owner"}))
	_, err := tool.Call(context.Background(), json.RawMessage(`{
		"owner":"owner","name":"repo","path":"f.md",
		"content":"x","branch":"feat/x"
	}`))
	require.Error(t, err)
	assert.ErrorIs(t, err, gitea.ErrValidation)
}