"""根图（第 1 页）：左栏层次页符号 + 右侧内嵌 drawio 框图 PNG。

跨页连接一律用全局标签，层次页不需要 sheet pin。子页的 sheet_uuid 由 uid("sh", 文件名)
推出，与 page.Page 的约定一致，所以根图和子图可以各自单独重生成。

    from schgen.root import write_root
    write_root(prj, [("02_Power.kicad_sch", "02 电源"), ...], png=r"...\\diagram.png",
               title="MyBoard", note="一段说明文字")

插图：KiCad 对没有 pHYs 的 PNG 按 300DPI 解释，scale=1 时宽 = 像素/300*25.4mm（G-0022），
据此反算 scale；(image (at 中心)) 给的是中心不是左上角；base64 每行 76 字符。
"""
import base64
import io
import os
import struct

from .kicad_lib import uid, esc
from .layout import PAPER

KICAD_BITMAP_DPI = 300.0


def image_block(png, x0, y0, max_w, max_h, key="img"):
    raw = io.open(png, "rb").read()
    px, py = struct.unpack(">II", raw[16:24])
    nat_w, nat_h = px / KICAD_BITMAP_DPI * 25.4, py / KICAD_BITMAP_DPI * 25.4
    scale = min(max_w / nat_w, max_h / nat_h)
    w, h = nat_w * scale, nat_h * scale
    cx, cy = x0 + w / 2.0, y0 + h / 2.0
    b64 = base64.b64encode(raw).decode("ascii")
    body = "\n\t\t\t".join('"%s"' % b64[i:i + 76] for i in range(0, len(b64), 76))
    blk = ('\t(image\n\t\t(at %.3f %.3f)\n\t\t(scale %.6f)\n\t\t(uuid "%s")\n'
           '\t\t(data %s\n\t\t)\n\t)' % (cx, cy, scale, uid("root", key, os.path.basename(png)), body))   # 只用文件名：工程搬目录后重生成结果不变
    return blk, (x0, y0, w, h)


def write_root(prj, sheets, png=None, title=None, note="", paper="A2",
               col_w=110.0, sheet_h=18.0, gap=10.0, img_note=None):
    """sheets: [(文件名, 显示名), ...]，按顺序排在左栏（页码 2、3…）。"""
    PW, PH = PAPER[paper]
    title = title or prj.name
    root_u = uid("root", prj.name)
    out = ['(kicad_sch (version 20231120) (generator "kicad_flow_schgen") (generator_version "8.0")',
           '  (uuid "%s")' % root_u,
           '  (paper "%s")' % paper,
           '  (title_block (title "%s") (rev "%s") (company "%s"))'
           % (esc(title), prj.rev, esc(prj.company)),
           '  (lib_symbols)']
    x = 26.0
    y = 24.0
    if note:
        out.append('  (text "%s" (at %.1f %.1f 0) (effects (font (size 1.8 1.8)) (justify left top))'
                   ' (uuid "%s"))' % (esc(note), x, y, uid("root", "note")))
        y += 6.0 + 2.6 * (note.count("\n") + 1)
    for i, (fn, name) in enumerate(sheets):
        sy = y + 6.0 + i * (sheet_h + gap)
        out.append(
            '  (sheet (at %.1f %.1f) (size %.1f %.1f) (fields_autoplaced yes)\n'
            '    (stroke (width 0.1524) (type solid)) (fill (color 0 0 0 0.0))\n'
            '    (uuid "%s")\n'
            '    (property "Sheetname" "%s" (at %.1f %.2f 0)\n'
            '      (effects (font (size 1.8 1.8)) (justify left bottom)))\n'
            '    (property "Sheetfile" "%s" (at %.1f %.2f 0)\n'
            '      (effects (font (size 1.4 1.4)) (justify left top)))\n'
            '    (instances (project "%s" (path "/%s" (page "%d"))))\n'
            '  )' % (x, sy, col_w, sheet_h, uid("sh", fn), esc(name), x, sy - 1.0,
                     fn, x, sy + sheet_h + 1.0, prj.name, root_u, i + 2))
    info = None
    if png:
        ix0 = x + col_w + 14.0
        iy0 = 24.0
        blk, info = image_block(png, ix0, iy0, PW - 14.0 - ix0, PH - 40.0 - iy0 - 8.0)
        out.append(blk)
        if img_note:
            out.append('  (text "%s" (at %.1f %.1f 0) (effects (font (size 1.6 1.6)) (justify left top))'
                       ' (uuid "%s"))' % (esc(img_note), ix0, iy0 + info[3] + 3.0,
                                          uid("root", "imgnote")))
    out.append('  (sheet_instances (path "/" (page "1")))')
    out.append(')')
    p = os.path.join(prj.out_dir, prj.name + ".kicad_sch")
    io.open(p, "w", encoding="utf-8").write("\n".join(out) + "\n")
    print("根图 %s (%.0f KB)%s" % (p, os.path.getsize(p) / 1024.0,
                                  "  框图 %.0fx%.0f mm" % (info[2], info[3]) if info else ""))
    return p


def write_project(prj):
    """最小 .kicad_pro（没有它 KiCad 打不开工程）；已存在就不动。"""
    p = os.path.join(prj.out_dir, prj.name + ".kicad_pro")
    if not os.path.exists(p):
        io.open(p, "w", encoding="utf-8").write(
            '{\n  "meta": {"filename": "%s.kicad_pro", "version": 1},\n'
            '  "schematic": {"legacy_lib_dir": "", "legacy_lib_list": []},\n'
            '  "sheets": [],\n  "boards": [],\n  "libraries": {"pinned_footprint_libs": [],'
            ' "pinned_symbol_libs": []}\n}\n' % prj.name)
    return p


def write_lib_tables(prj, sym_libs=(), fp_libs=()):
    """工程级 sym-lib-table / fp-lib-table，用 ${KIPRJMOD} 相对路径。
    改完必须**整个退出 KiCad 再重启**才生效（G-0020）。"""
    def table(kind, libs):
        rows = ['(%s_lib_table' % kind, '  (version 7)']
        for name, rel in libs:
            # 绝对路径原样写；ipots 工程里 ${KIPRJMOD} 版 fp-lib-table 曾没被认到（多半是没重启）
            uri = rel if os.path.isabs(rel) else "${KIPRJMOD}/" + rel
            rows.append('  (lib (name "%s") (type "KiCad") (uri "%s") (options "")'
                        ' (descr ""))' % (name, uri.replace("\\", "/")))
        rows.append(')')
        return "\n".join(rows) + "\n"
    if sym_libs:
        io.open(os.path.join(prj.out_dir, "sym-lib-table"), "w", encoding="utf-8").write(
            table("sym", sym_libs))
    if fp_libs:
        io.open(os.path.join(prj.out_dir, "fp-lib-table"), "w", encoding="utf-8").write(
            table("fp", fp_libs))