package api

import (
	"encoding/json"
	"errors"
	"net/http"

	"github.com/jackc/pgx/v5"

	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
	"git.fabledsword.com/bvandeusen/minstrel/internal/importer"
	"git.fabledsword.com/bvandeusen/minstrel/internal/lifecycle"
)

// Downloads and their imports (M502 #5522): the Wanted view's Activity tab,
// a person's "import anyway", "refuse" and "retry", and the Blocked tab.

// downloadView is one grab and what its import made of it.
type downloadView struct {
	ID            string             `json:"id"`
	WantID        *string            `json:"want_id"`
	WantTitle     string             `json:"want_title"`
	WantArtist    string             `json:"want_artist"`
	Name          string             `json:"name"`
	Indexer       string             `json:"indexer"`
	Client        string             `json:"client"`
	Quality       string             `json:"quality"`
	Origin        string             `json:"origin"`
	GrabbedAt     string             `json:"grabbed_at"`
	EndedAt       *string            `json:"ended_at"`
	EndReason     string             `json:"end_reason"`
	Progress      float32            `json:"progress"`
	ImportState   string             `json:"import_state"`
	ImportReason  string             `json:"import_reason"`
	ImportedAt    *string            `json:"imported_at"`
	ImportedFiles int32              `json:"imported_files"`
	Destination   string             `json:"destination"`
	Edition       string             `json:"edition,omitempty"`
	Evidence      *importer.Evidence `json:"evidence,omitempty"`
	Files         []string           `json:"files"`
	Skipped       int                `json:"skipped"`
	RehomedFrom   string             `json:"rehomed_from,omitempty"`
	// EndDetail says why an ended download ended (#5523).
	EndDetail string `json:"end_detail"`
	// Seeding: imported and still sharing; Ratio its share ratio as last
	// read; SeedReleasedAt when it was removed once it had shared enough.
	Seeding        bool    `json:"seeding"`
	Ratio          float32 `json:"ratio"`
	SeedReleasedAt *string `json:"seed_released_at"`
	// Condition is what is wrong with it now, if anything.
	Condition *conditionView `json:"condition"`
}

// conditionView is an open row of the intervention ledger: what was seen,
// since when, and how many times it was retried.
type conditionView struct {
	Trigger string `json:"trigger"`
	Detail  string `json:"detail"`
	Retries int32  `json:"retries"`
	Since   string `json:"since"`
}

func downloadFrom(g dbq.ListGrabsRow) downloadView {
	v := downloadView{
		ID: uuidToString(g.ID), Name: g.Name, Indexer: g.Indexer, Client: g.Client, Quality: g.Quality,
		Origin: g.Origin, GrabbedAt: formatTimestamp(g.GrabbedAt), EndReason: g.EndReason,
		Progress: g.Progress, ImportState: g.ImportState, ImportReason: g.ImportReason,
		ImportedFiles: g.ImportedFiles, Destination: g.Destination, Files: []string{},
		EndDetail: g.EndDetail, Seeding: g.Seeding, Ratio: g.Ratio,
	}
	if g.SeedReleasedAt.Valid {
		at := formatTimestamp(g.SeedReleasedAt)
		v.SeedReleasedAt = &at
	}
	if g.Condition != nil {
		v.Condition = &conditionView{Trigger: *g.Condition, Detail: deref(g.ConditionDetail),
			Since: formatTimestamp(g.ConditionSince)}
		if g.ConditionRetries != nil {
			v.Condition.Retries = *g.ConditionRetries
		}
	}
	if g.WantID.Valid {
		id := uuidToString(g.WantID)
		v.WantID = &id
	}
	if g.WantTitle != nil {
		v.WantTitle = *g.WantTitle
	}
	if g.WantArtist != nil {
		v.WantArtist = *g.WantArtist
	}
	if g.EndedAt.Valid {
		at := formatTimestamp(g.EndedAt)
		v.EndedAt = &at
	}
	if g.ImportedAt.Valid {
		at := formatTimestamp(g.ImportedAt)
		v.ImportedAt = &at
	}
	var det importer.Detail
	if len(g.ImportDetail) > 0 && json.Unmarshal(g.ImportDetail, &det) == nil && det.Verdict.Outcome != "" {
		ev := det.Verdict.Evidence
		v.Evidence, v.Edition, v.Skipped, v.RehomedFrom = &ev, det.Edition, det.Skipped, det.RehomedFrom
		if det.Files != nil {
			v.Files = det.Files
		}
	}
	return v
}

type downloadsPage struct {
	Items  []downloadView `json:"items"`
	Limit  int            `json:"limit"`
	Offset int            `json:"offset"`
	// ClientsDown are the download clients not answering now (#5523).
	ClientsDown []clientDownView `json:"clients_down"`
}

type clientDownView struct {
	Client string `json:"client"`
	Detail string `json:"detail"`
	Since  string `json:"since"`
}

// handleListDownloads implements GET /api/admin/downloads?offset=: running
// downloads first, then the rest newest first.
func (h *handlers) handleListDownloads(w http.ResponseWriter, r *http.Request) {
	limit, offset, err := parsePaging(r.URL.Query())
	if err != nil {
		writeErr(w, apierror.BadRequest("invalid_paging", "limit and offset must be numbers"))
		return
	}
	rows, err := dbq.New(h.pool).ListGrabs(r.Context(), dbq.ListGrabsParams{MaxRows: int32(limit), Skip: int32(offset)})
	if err != nil {
		writeErrWithLog(w, h.logger, "admin downloads: list", apierror.Internal(err))
		return
	}
	down, err := dbq.New(h.pool).ListClientsDown(r.Context())
	if err != nil {
		writeErrWithLog(w, h.logger, "admin downloads: clients down", apierror.Internal(err))
		return
	}
	out := downloadsPage{Items: make([]downloadView, 0, len(rows)), Limit: limit, Offset: offset,
		ClientsDown: make([]clientDownView, 0, len(down))}
	for _, g := range rows {
		out.Items = append(out.Items, downloadFrom(g))
	}
	for _, c := range down {
		out.ClientsDown = append(out.ClientsDown, clientDownView{Client: c.Client, Detail: c.Detail,
			Since: formatTimestamp(c.FirstSeen)})
	}
	writeJSON(w, http.StatusOK, out)
}

// handleAbandonDownload implements POST /api/admin/downloads/{id}/abandon: a
// running download is given up, its release set aside, the download removed
// and the album searched again.
func (h *handlers) handleAbandonDownload(w http.ResponseWriter, r *http.Request) {
	admin, ok := requireUser(w, r)
	if !ok {
		return
	}
	id, ok := requireURLUUID(w, r, "id")
	if !ok {
		return
	}
	if _, err := h.lifecycle.Abandon(r.Context(), id, admin.ID); err != nil {
		switch {
		case errors.Is(err, pgx.ErrNoRows), errors.Is(err, lifecycle.ErrNotAbandonable):
			writeErr(w, apierror.Conflict("not_running", "that download is no longer running"))
		default:
			writeErrWithLog(w, h.logger, "admin downloads: abandon", apierror.Internal(err))
		}
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// handleImportAnyway implements POST /api/admin/downloads/{id}/import: a
// download the check held for a person (or one that failed) is imported on
// the next pass whatever the check says.
func (h *handlers) handleImportAnyway(w http.ResponseWriter, r *http.Request) {
	id, ok := requireURLUUID(w, r, "id")
	if !ok {
		return
	}
	if _, err := dbq.New(h.pool).ForceGrabImport(r.Context(), id); err != nil {
		h.writeImportErr(w, "import anyway", err)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// handleRetryImport implements POST /api/admin/downloads/{id}/retry.
func (h *handlers) handleRetryImport(w http.ResponseWriter, r *http.Request) {
	id, ok := requireURLUUID(w, r, "id")
	if !ok {
		return
	}
	if _, err := dbq.New(h.pool).RetryGrabImport(r.Context(), id); err != nil {
		h.writeImportErr(w, "retry", err)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

// handleRefuseDownload implements POST /api/admin/downloads/{id}/refuse: the
// release is blocked, the download removed and the album searched again.
func (h *handlers) handleRefuseDownload(w http.ResponseWriter, r *http.Request) {
	admin, ok := requireUser(w, r)
	if !ok {
		return
	}
	id, ok := requireURLUUID(w, r, "id")
	if !ok {
		return
	}
	if _, err := h.importer.Refuse(r.Context(), id, admin.ID); err != nil {
		h.writeImportErr(w, "refuse", err)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func (h *handlers) writeImportErr(w http.ResponseWriter, what string, err error) {
	switch {
	case errors.Is(err, pgx.ErrNoRows), errors.Is(err, importer.ErrNotDecidable):
		writeErr(w, apierror.Conflict("not_decidable", "that download is not waiting on a decision"))
	default:
		writeErrWithLog(w, h.logger, "admin downloads: "+what, apierror.Internal(err))
	}
}

type releaseBlockView struct {
	InfoHash  string `json:"info_hash"`
	Name      string `json:"name"`
	Reason    string `json:"reason"`
	Detail    string `json:"detail"`
	BlockedAt string `json:"blocked_at"`
	// ExpiresAt is when a release given up on may be taken again; null is
	// for good (#5523).
	ExpiresAt  *string `json:"expires_at"`
	WantTitle  string  `json:"want_title"`
	WantArtist string  `json:"want_artist"`
}

type releaseBlocksPage struct {
	Items  []releaseBlockView `json:"items"`
	Limit  int                `json:"limit"`
	Offset int                `json:"offset"`
}

// handleListReleaseBlocks implements GET /api/admin/release-blocks?offset=:
// every release set aside, by a person or by a check, newest first.
func (h *handlers) handleListReleaseBlocks(w http.ResponseWriter, r *http.Request) {
	limit, offset, err := parsePaging(r.URL.Query())
	if err != nil {
		writeErr(w, apierror.BadRequest("invalid_paging", "limit and offset must be numbers"))
		return
	}
	rows, err := dbq.New(h.pool).ListReleaseBlocksPage(r.Context(), dbq.ListReleaseBlocksPageParams{
		MaxRows: int32(limit), Skip: int32(offset)})
	if err != nil {
		writeErrWithLog(w, h.logger, "admin release blocks: list", apierror.Internal(err))
		return
	}
	out := releaseBlocksPage{Items: make([]releaseBlockView, 0, len(rows)), Limit: limit, Offset: offset}
	for _, b := range rows {
		v := releaseBlockView{InfoHash: b.InfoHash, Name: b.Name, Reason: b.Reason, Detail: b.Detail,
			BlockedAt: formatTimestamp(b.BlockedAt)}
		if b.ExpiresAt.Valid {
			at := formatTimestamp(b.ExpiresAt)
			v.ExpiresAt = &at
		}
		if b.WantTitle != nil {
			v.WantTitle = *b.WantTitle
		}
		if b.WantArtist != nil {
			v.WantArtist = *b.WantArtist
		}
		out.Items = append(out.Items, v)
	}
	writeJSON(w, http.StatusOK, out)
}