import re
import gradio as gr
import sympy as sp
from sympy.parsing.sympy_parser import (
    parse_expr, standard_transformations,
    implicit_multiplication_application, convert_xor
)

TITLE = "LanguageBridge — Math Fast Agent (SymPy)"

# ---------- 輸入正規化：隱式乘法 / ^→** / 全形→半形 / √→sqrt ----------
def normalize_ascii(s: str) -> str:
    table = str.maketrans({
        '（':'(', '）':')', '，':',', '；':';', '：':':',
        '＝':'=', '－':'-', '＋':'+', '＊':'*', '／':'/', '。':'.',
        '×':'*', '√':'sqrt'
    })
    return s.translate(table)

def auto_insert_stars(s: str) -> str:
    s = re.sub(r'(\d)([A-Za-z])', r'\1*\2', s)   # 3x -> 3*x
    s = re.sub(r'([A-Za-z0-9_])\(', r'\1*(', s)   # x( -> x*(
    s = re.sub(r'\)([A-Za-z0-9_])', r')*\1', s)   # )x -> )*x
    s = re.sub(r'(\d)\s*sqrt', r'\1*sqrt', s)     # 2sqrt -> 2*sqrt
    return s

def preprocess(expr: str) -> str:
    s = (expr or "").strip()
    s = normalize_ascii(s)
    s = s.replace("^", "**")      # 2^3 -> 2**3
    s = auto_insert_stars(s)      # 隱式乘法 -> 顯式
    return s

TRANS = standard_transformations + (implicit_multiplication_application, convert_xor)

def to_sympy_expr(s: str):
    s = preprocess(s)
    return parse_expr(s, transformations=TRANS)

def to_sympy_eq(s: str):
    s = preprocess(s)
    if "=" not in s:
        raise ValueError("等式缺少 '='")
    L, R = s.split("=", 1)
    return sp.Eq(parse_expr(L, transformations=TRANS),
                 parse_expr(R, transformations=TRANS))

def solve_math(q: str):
    q = (q or "").strip()
    if not q:
        return "請輸入算式或方程，例如：2x+3=11；sin(x)^2 + cos(x)^2；factor(x^2-9)"
    try:
        parts = [s.strip() for seg in q.split(";") for s in seg.split("\n")]
        parts = [p for p in parts if p]

        # 有 '=' 就走解方程（可聯立）
        if any("=" in p for p in parts):
            eqs, syms = [], set()
            for s in parts:
                if "=" in s:
                    e = to_sympy_eq(s)
                    eqs.append(e)
                    syms |= e.free_symbols | e.rhs.free_symbols
            if not syms:
                syms = {sp.symbols("x")}
            sol = sp.solve(eqs, list(syms), dict=True)
            if not sol:
                return "無解或需要更多條件。"
            return "\n".join(
                f"解 {i}: " + ", ".join([f\"{k} = {sp.simplify(v)}\" for k, v in d.items()])
                for i, d in enumerate(sol, 1)
            )

        # 否則當一般表達式：簡化/因式/微分/積分
        expr = to_sympy_expr(q)
        out = []
        try: out.append(f"簡化：{sp.simplify(expr)}")
        except Exception: out.append(f"簡化：{expr}")
        try:
            fact = sp.factor(expr)
            if fact != expr: out.append(f"因式分解：{fact}")
        except Exception: pass
        try:
            x = next(iter(expr.free_symbols)) if expr.free_symbols else sp.symbols("x")
            out.append(f"對 {x} 微分：{sp.diff(expr, x)}")
            out.append(f"對 {x} 積分：{sp.integrate(expr, x)}")
        except Exception: pass
        return "\n".join(out) if out else f"結果：{expr}"
    except Exception as e:
        return f"解析失敗：{e}"

with gr.Blocks(title=TITLE) as demo:
    gr.Markdown(
        "## " + TITLE + "\\n"
        "貼上算式（可多行 / 用分號 `;` 分隔）。\\n\\n"
        "**可直接輸入隱式乘法：** `3x`、`2(x+1)`、`(x)(x+1)`、`2sqrt(x)`；"
        "也可用 `x^2`（自動轉為 `x**2`），`√(x)`（自動轉為 `sqrt(x)`）。"
    )
    q = gr.Textbox(lines=6, label="題目 / 算式（可含聯立方程）")
    out = gr.Textbox(lines=12, label="輸出")
    gr.Button("送出 🚀").click(fn=solve_math, inputs=q, outputs=out)

if __name__ == "__main__":
    demo.launch()   # 在 Space 環境不用 share