// giteaapi.go — 以 internal/gitea 的 HTTP 用戶端實作 workflow.Client。
//
// 端點與查詢參數對照 gitea.py：清單一律帶 limit 分頁（ListAll 固定 50）；
// issues 端點帶 type=issues（排除 PR）與 state=open；pulls 帶 state=open。
package workflow

import (
	"context"
	"errors"
	"net/url"
	"strconv"

	"gitea.alterminal.com/alterminal/teai/internal/gitea"
)

// errNoUsername 表示 /user 回應中找不到帳號名（伺服端回應異常）。
var errNoUsername = errors.New("gitea: GET /user: response has no username")

// APIClient 是 Client 介面的 HTTP 實作，包裝 internal/gitea.Client。
type APIClient struct {
	Client *gitea.Client
}

// 確認 APIClient 實作 Client 介面（編譯期檢查）。
var _ Client = (*APIClient)(nil)

func (a *APIClient) CurrentUser() (string, error) {
	var u User
	if err := a.Client.GetJSON(context.Background(), "/user", &u); err != nil {
		return "", err
	}
	name := u.Name()
	if name == "" {
		return "", errNoUsername
	}
	return name, nil
}

func (a *APIClient) ListOrgs() ([]string, error) {
	var orgs []Org
	if err := a.Client.ListAll(context.Background(), "/user/orgs", gitea.ListOptions{}, &orgs); err != nil {
		return nil, err
	}
	names := make([]string, 0, len(orgs))
	for _, o := range orgs {
		if n := o.Account(); n != "" {
			names = append(names, n)
		}
	}
	return names, nil
}

func (a *APIClient) ListTeams(org string) ([]Team, error) {
	var teams []Team
	path := "/orgs/" + url.PathEscape(org) + "/teams"
	if err := a.Client.ListAll(context.Background(), path, gitea.ListOptions{}, &teams); err != nil {
		return nil, err
	}
	return teams, nil
}

func (a *APIClient) ListTeamMembers(teamID int64) ([]string, error) {
	var users []User
	path := "/teams/" + strconv.FormatInt(teamID, 10) + "/members"
	if err := a.Client.ListAll(context.Background(), path, gitea.ListOptions{}, &users); err != nil {
		return nil, err
	}
	names := make([]string, 0, len(users))
	for i := range users {
		if n := users[i].Name(); n != "" {
			names = append(names, n)
		}
	}
	return names, nil
}

func (a *APIClient) ListOrgRepos(org string) ([]Repo, error) {
	var repos []Repo
	path := "/orgs/" + url.PathEscape(org) + "/repos"
	if err := a.Client.ListAll(context.Background(), path, gitea.ListOptions{}, &repos); err != nil {
		return nil, err
	}
	return repos, nil
}

func (a *APIClient) ListIssues(owner, repo string) ([]Issue, error) {
	var issues []Issue
	path := "/repos/" + url.PathEscape(owner) + "/" + url.PathEscape(repo) + "/issues"
	opts := gitea.ListOptions{Extra: url.Values{
		"type":  {"issues"},
		"state": {"open"},
	}}
	if err := a.Client.ListAll(context.Background(), path, opts, &issues); err != nil {
		return nil, err
	}
	// /issues 也會回傳 PR（帶 pull_request 欄位）；一律排除。
	out := make([]Issue, 0, len(issues))
	for i := range issues {
		if issues[i].PullRequest == nil {
			out = append(out, issues[i])
		}
	}
	return out, nil
}

func (a *APIClient) ListPulls(owner, repo string) ([]PullRequest, error) {
	var pulls []PullRequest
	path := "/repos/" + url.PathEscape(owner) + "/" + url.PathEscape(repo) + "/pulls"
	opts := gitea.ListOptions{Extra: url.Values{"state": {"open"}}}
	if err := a.Client.ListAll(context.Background(), path, opts, &pulls); err != nil {
		return nil, err
	}
	return pulls, nil
}

func (a *APIClient) ListComments(owner, repo string, number int64) ([]Comment, error) {
	var comments []Comment
	path := "/repos/" + url.PathEscape(owner) + "/" + url.PathEscape(repo) +
		"/issues/" + strconv.FormatInt(number, 10) + "/comments"
	if err := a.Client.ListAll(context.Background(), path, gitea.ListOptions{}, &comments); err != nil {
		return nil, err
	}
	return comments, nil
}

// ── StalledSource 面向（#7 CLI 接線）────────────────────────────────────
// APIClient 在 Client 之外同時實作 StalledSource（Source + CurrentUser +
// GetIssue），讓 stalled／xrefs 命令與既有命令共用同一個 HTTP 用戶端。
// 清單類方法直接委派 Client 同名操作，語義一致（type=issues、state=open）。

// GetIssue 單一 issue 查詢（PR 亦經此端點，帶 pull_request 標記）；
// 失敗（含 404）回 *gitea.ErrAPI，由 CLI 映射結束碼 3。
func (a *APIClient) GetIssue(owner, repo string, number int64) (Issue, error) {
	var issue Issue
	path := "/repos/" + url.PathEscape(owner) + "/" + url.PathEscape(repo) +
		"/issues/" + strconv.FormatInt(number, 10)
	if err := a.Client.GetJSON(context.Background(), path, &issue); err != nil {
		return Issue{}, err
	}
	return issue, nil
}

// TryGetIssue 寬容版單一 issue 查詢：失敗（含 404）回 (零值, false, nil)，
// 供 stalled 父追蹤項掃描靜默略過不存在的子項（Source 介面契約）。
func (a *APIClient) TryGetIssue(owner, repo string, number int64) (Issue, bool, error) {
	issue, err := a.GetIssue(owner, repo, number)
	if err != nil {
		return Issue{}, false, nil
	}
	return issue, true, nil
}

// IssueTimeline 回傳 issue 的 timeline 事件（Source 面向；對應 gitea.py
// _direct_last_activity 拉取的 repos/{o}/{r}/issues/{n}/timeline）。
// 分頁由 ListAll 處理（與 gitea.py api_get_list 的 limit=50 逐頁一致）。
func (a *APIClient) IssueTimeline(owner, repo string, number int64) ([]TimelineEvent, error) {
	var events []TimelineEvent
	path := "/repos/" + url.PathEscape(owner) + "/" + url.PathEscape(repo) +
		"/issues/" + strconv.FormatInt(number, 10) + "/timeline"
	if err := a.Client.ListAll(context.Background(), path, gitea.ListOptions{}, &events); err != nil {
		return nil, err
	}
	return events, nil
}

// MyOrganizations 委派 ListOrgs（Source 面向）。
func (a *APIClient) MyOrganizations() ([]string, error) { return a.ListOrgs() }

// OrganizationRepositories 委派 ListOrgRepos（Source 面向）。
func (a *APIClient) OrganizationRepositories(org string) ([]Repo, error) {
	return a.ListOrgRepos(org)
}

// OpenIssues 委派 ListIssues（Source 面向；已排除 PR）。
func (a *APIClient) OpenIssues(owner, repo string) ([]Issue, error) {
	return a.ListIssues(owner, repo)
}

// OpenPulls 委派 ListPulls（Source 面向）。
func (a *APIClient) OpenPulls(owner, repo string) ([]PullRequest, error) {
	return a.ListPulls(owner, repo)
}

// IssueComments 委派 ListComments（Source 面向）。
func (a *APIClient) IssueComments(owner, repo string, number int64) ([]Comment, error) {
	return a.ListComments(owner, repo, number)
}

// ── MilestoneSource 面向（#31 跨倉庫里程碑總覽）────────────────────────
// APIClient 在 StalledSource 之外另實作 MilestoneSource，讓 milestones
// 總覽命令與既有命令共用同一個 HTTP 用戶端；查詢參數對照 gitea.py 的
// list_open_milestones_for_repository／_milestone_open_issues。

// OpenMilestones 回傳倉庫的 open 里程碑（GET /repos/{o}/{r}/milestones?state=open）。
func (a *APIClient) OpenMilestones(owner, repo string) ([]Milestone, error) {
	var ms []Milestone
	path := "/repos/" + url.PathEscape(owner) + "/" + url.PathEscape(repo) + "/milestones"
	opts := gitea.ListOptions{Extra: url.Values{"state": {"open"}}}
	if err := a.Client.ListAll(context.Background(), path, opts, &ms); err != nil {
		return nil, err
	}
	return ms, nil
}

// MilestoneOpenIssues 回傳掛在指定里程碑（依名稱過濾，Gitea 以
// milestones=<title> 查詢）的 open 條目。刻意**不**帶 type=issues——
// PR 亦屬里程碑條目，保留兩者供覆蓋檢查（同 gitea.py
// _milestone_open_issues；PR 帶 pull_request 標記由 workflow 判別）。
func (a *APIClient) MilestoneOpenIssues(owner, repo, milestoneTitle string) ([]Issue, error) {
	var issues []Issue
	path := "/repos/" + url.PathEscape(owner) + "/" + url.PathEscape(repo) + "/issues"
	opts := gitea.ListOptions{Extra: url.Values{
		"state":      {"open"},
		"milestones": {milestoneTitle},
	}}
	if err := a.Client.ListAll(context.Background(), path, opts, &issues); err != nil {
		return nil, err
	}
	return issues, nil
}

// 編譯期確認 APIClient 同時實作 Client、StalledSource 與 MilestoneSource。
var _ StalledSource = (*APIClient)(nil)
var _ MilestoneSource = (*APIClient)(nil)